1. Field of the Invention
The present invention relates to an electromagnetic relay. The size of the electromagnetic relay according to the present invention is, for example, 20 mm.times.10 mm.times.15 mm.
2. Description of the Prior Art
In general, the electromagnet of an electromagnetic relay consists of a bobbin, a coil, a fixed magnetic core, and a movable armature. The armature is adapted so as to be actuated upon excitation of the coil and thus is attracted to the fixed magnetic core. Usually in such electromagnet, the central portion of the U-shaped fixed magnetic core is inserted into the central hole of the bobbin and the two legs of the U-shaped core protrude outside the bobbin. The armature is also located outside the bobbin so as to bridge the two legs of the U-shaped core. Such a structure can be called an external armature-type structure.
In such a structure of the electromagnet, there is a problem in that utilization of the generated magnetic flux is unsatisfactory. Usually, only 60% of the generated magnetic flux is utilized as the operation force of the electromagnet. Accordingly, the electrical power supplied to the electromagnet cannot be satisfactorily utilized in the operation of the electromagnetic relay.